By: Ashley, Kelsey, Devin, Jarred, Shaq

Spheres By: Ashley, Kelsey, Devin, Jarred, Shaq

Surface area formula • SA=4πr^2 Finding a radius • EX. SA=30in plug it back into formula • SA=4πr^2 • 30in=4πr^2 divide by 4π to both sides • 2.38in=r^2 then your Square root • 2.38in=√r^2 • R=1.55in • Now plugging it back into the formula to find SA • SA=4πr^2 • SA=4π(1.55in)^2 • SA=30in^2 Remember to square your units cause its SA

Volume Formula

MM2G4B Determining the effect on surface area and volume of changing the radius of a sphere.

Surface area • When you double the radius the surface area changes by a multiple of 4 • So, when you triple the radius the surface area changes by a multiple of 9 • Double (2) radius  X4 • Triple (3) radius  X9

Volume • If you double the radius the volume changes to a multiple of 8 • So, if you triple the radius the volume changes to a multiple of 27 • Double (2) radius X8 • Triple (3) radius  X27

SA=4πr² R=1 SA=4π(1)² SA=4π1 SA=4π SA=12.6 Double it R=2 SA=4π(2)² SA=4π4 SA=16π SA=50.3 12.6 x 4 SA=50.4 Examples of surface area

V=4πr³/3 R=4 V=4π(4)³/3 V=85.3 Double it r=8 V=4π(8)³/3 V=682.7 V=85.3 x 8=682.4 Examples of Volume

By: Ashley, Kelsey, Devin, Jarred, Shaq